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PTGT04
08-19-2006, 02:52 PM
I have a 2004 PT Cruiser GT. It has 41000mi. on it. I have a bad vibration only during decceleration. When I drive at high speeds, or with the cruise on, or when I accelerate to any speed I have no Problems. But when I am going on the highway at say 85mph and take my foot off the gas pedal to coast down to legal speed I have a bad vibration. I have checked the front end parts and the cv joints, wheel balance is ok also. This problem happens only when I am coasting on the highway. Any help would be appreciated.

ottawa rogue
08-19-2006, 03:09 PM
does this happen at a specific speed range, like between 55-60mph?
since it only happens during coast and decel, that would tend to rule out cv joints.
usually a high speed vibe like that is a tire issue, either balance or tire runout
(out of round)

PTGT04
08-20-2006, 07:35 AM
This happens at all speeds on highway driving, as soon as I lift my foot from the pedal. Don't notice it in stop and go or city driving. Some people have said maybe motor mount, I have polyurethne mounts inatlled on both upper and lower, control arm bushing are good also, some people have said they go bad on PT's, mine are still good. Is there a way I can check tire runout, they balanced out good on the machine yesterday. Thank for the help

ottawa rogue
08-20-2006, 12:20 PM
basically, you put it back on the balance machine and spin it by hand slowly.
just look for any funny side to side motion or "hopping" of the tread.
the motor mount thing might also be something to check out, you could have one sagging or the engine could have gotten uncentered. (is this possible on a PT?):confused:

turbovanmanČ
08-20-2006, 05:31 PM
Well the balancer theory will only work if the shop has the new one, that actually puts a load on the tire using a roller otherwise the regular one won't pick up a seperated tire at speed. Swap the tires to the back and see if it changes or put a set of known good tires/rims on. If its still there, I would be inclined to guess at a CV joint going bad.

PTGT04
08-26-2006, 04:11 PM
I found out what the problem was, Somebody(probably daughter) put in a can of fix a flat in the passenger front tire, didn't tell me and still hasn't. It balanced out ok and ran good at acceleration but when I took my foot off the gas that stuff started sloshing around like crazy. I also was told that the rim was corroded on the lip where the tire bead met the rim. I have heard this about chrysler rims. Thanks for all your help.

ottawa rogue
08-28-2006, 12:30 PM
DOH!!!!!:banghead: :banghead: :banghead:

don't ya love it when that happens:D

oh, and fix a flat will corrode any rim if left in there too long

ottawa rogue
08-28-2006, 12:33 PM
Well the balancer theory will only work if the shop has the new one, that actually puts a load on the tire using a roller otherwise the regular one won't pick up a seperated tire at speed. Swap the tires to the back and see if it changes or put a set of known good tires/rims on. If its still there, I would be inclined to guess at a CV joint going bad.

they have a balancer that measures runout? Cool!
it's been a few years since i worked in an auto shop:D
the main thing i was talking about is gross (obvious) runout

turbovanmanČ
08-28-2006, 01:00 PM
they have a balancer that measures runout? Cool!
it's been a few years since i worked in an auto shop:D
the main thing i was talking about is gross (obvious) runout

Yes, state of the art, its for problems just like this. It looks like something out of the twilight zone, :nod: